The invention relates to a rollback carrier that uses a gravity-based tilt system to lower and raise a truck bed into loading and transport positions. A conventional carrier, in contrast, has an independent set of hydraulic tilt cylinders specifically to actuate and control the tilting of the bed no matter the horizontal position of the bed, load or center of gravity.
The gravity-based system makes use of a rear stabilizer frame that is deployed and articulated to control the tilting function of the bed once the operator moves the combined center of gravity of the bed and the cargo (equipment, vehicle, etc.) horizontally (forward/aft) beyond the pivot point on the chassis. If the center of gravity is behind the pivot point, the bed will tend to tilt down into the loading position. If the center of gravity is forward of the pivot point, the bed will tend to tilt back to the flat transport position.
The invention addresses a service life concern with the existing gravity-based tilt design in the event of a loaded bed rapidly lowering or raising. The concern also arises if more than one piece of heavy equipment is loaded front to back on the bed. If the rear stabilizer frame is not deployed at the correct time or distance, the bed and any cargo on it will lower rapidly into the loading or transport position, providing the operator minimal time to react. In the case of multiple pieces of equipment loaded on the bed, when one piece of equipment is unloaded or loaded behind the first piece, the operational dynamics and center of gravity changes significantly, which could leave an inexperienced or inattentive operator in a potentially unfamiliar situation. The possible results of these dynamic scenarios are:
a. shifting the loaded equipment into an undesirable position for transport or removal;
b. operator disorientation due to a dynamic event which was unexpected;
c. potential damage to the chassis;
d. potential damage to the ground surface or area under the carrier;
e. potential damage to objects behind or around the carrier
f. etc.